This invention relates to compounds useful as lubricant additives.
Amongst the numerous types of additives used in blending lubricants, particularly but not exclusively automotive lubricants, are various surface active materials. For example, dispersants, particularly ashless dispersants, are incorporated in lubricants in order to disperse carbon particles and other insoluble materials such as decomposition products and fuel oxidation products in the oil medium which is the major constituent of the lubricants. The insoluble materials are thus suspended in the oil medium and prevented from forming deposits which can deleteriously affect engine operation.
Among the ashless dispersants proposed for the foregoing purpose have been certain derivatives prepared by reacting long chain alkyl phenols with aldehydes and polyalkylene polyamines to give Mannich bases. These compounds are excellent dispersants and impart some degree of oxidation resistance to lubricants in which they are incorporated, but in general they are deficient in thermal stability and also tend to derate the performance of the oils in diesel applications.